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Ling51/Psych56L:AcquisitionofLanguage
Lecture10PhonologicaldevelopmentIII
Announcements
Beworkingonthephonologicaldevelopmentreviewquestions
BeworkingonHW3
Prelinguisticspeechperception
Infanthearing
Infanthearingisnotquiteassensitiveasadulthearing-buttheycanhearquitewellandrememberwhattheyhear.
Ex1:Fetuses38weeksoldAloudspeakerwasplaced10cmawayfromthemother’sabdomen.
Theheartrateofthefetuswentupinresponsetohearingarecordingofthemother’svoice,ascomparedtohearingarecordingofastranger’svoice.
Infanthearing
Infanthearingisnotquiteassensitiveasadulthearing-buttheycanhearquitewellandrememberwhattheyhear.
Ex2:NewbornsPregnantwomenreadapassageoutloudeverydayforthelast6
weeksoftheirpregnancy.Theirnewbornsshowedapreferenceforthatpassageoverotherpassagesreadbytheirmothers.
Infanthearing
Infanthearingisnotquiteassensitiveasadulthearing-buttheycanhearquitewellandrememberwhattheyhear.
Ex3:Newborns(Moon,Lagercrantz,&Kuhl2012)SwedishandEnglishnewbornshearddifferentambientlanguages
whileinthewomb(SwedishandEnglish,respectively),andweresurprisedwhentheyheardnon-nativevowelsonlyhoursafterbirth.
Studyinginfantspeechperceptionhttp://www.thelingspace.com/episode-16https://www.youtube.com/watch?v=3-A9TnuSVa8
beginningthrough3:34:HighAmplitudeSuckingProcedure(HAS)
StudyinginfantspeechperceptionResearchersuseindirectmeasurementtechniques.
HighAmplitudeSucking(HAS)
Infantsareawakeandinaquietlyalertstate.Theyareplacedinacomfortablereclinedchairandofferedasterilizedpacifierthatisconnectedtoapressuretransducerandacomputerviaapieceofrubbertubing.Oncetheinfanthasbegunsucking,thecomputermeasurestheinfant’saveragesuckingamplitude(strengthofthesucks).
StudyinginfantspeechperceptionResearchersuseindirectmeasurementtechniques.
HighAmplitudeSucking(HAS)
Asoundispresentedtotheinfanteverytimeastrongor“highamplitude”suckoccurs.Infantsquicklylearnthattheirsuckingcontrolsthesounds,andtheywillsuckmorestronglyandmoreoftentohearsoundstheylikethemost.Thesuckingratecanalsobemeasuredtoseeifaninfantnoticeswhennewsoundsareplayed.
Studyinginfantspeechperceptionhttp://www.thelingspace.com/episode-16https://www.youtube.com/watch?v=3-A9TnuSVa8
3:34-5:48:Head-TurnPreferenceProcedure
StudyinginfantspeechperceptionResearchersuseindirectmeasurementtechniques.
Head-TurnPreferenceProcedure
Infantsitsoncaretaker’slap.Thewallinfrontoftheinfanthasagreenlightmountedinthecenterofit.Thewallsonthesidesoftheinfanthaveredlightsmountedinthecenterofthem,andtherearespeakershiddenbehindtheredlights.
StudyinginfantspeechperceptionResearchersuseindirectmeasurementtechniques.
Head-TurnPreferenceProcedure
Soundsareplayedfromthetwospeakersmountedateye-leveltotheleftandrightoftheinfant.Thesoundsstartwhentheinfantlookstowardstheblinkingsidelight,andendwhentheinfantlooksawayformorethantwoseconds.
StudyinginfantspeechperceptionResearchersuseindirectmeasurementtechniques.
Head-TurnPreferenceProcedure
Thus,theinfantessentiallycontrolshowlongs/hehearsthesounds.Differentialpreferenceforonetypeofsoundovertheotherisusedasevidencethatinfantscandetectadifferencebetweenthetypesofsounds.
StudyinginfantspeechperceptionResearchersuseindirectmeasurementtechniques.
Head-TurnTechniquehttps://www.youtube.com/watch?v=WvM5bqUsbu8Especially0:31-1:15
StudyinginfantspeechperceptionResearchersuseindirectmeasurementtechniques.
Head-TurnTechnique
Babiestendtobeinterestedinmovingtoys.Usingthepresentationofamovingtoyasareward,babiesaretrainedtoturntheirheadswhentheyhearachangeinthesoundbeingpresented.
StudyinginfantspeechperceptionResearchersuseindirectmeasurementtechniques.
Head-TurnTechnique
Asoundisplayedoverandover,andthenthesoundischangedfollowedimmediatelybythepresentationofthemovingtoy.Afterseveraltrials,babiesturntheirheadswhenthesoundschangeevenbeforethemovingtoyisactivated.
Categoricalperception
Onefeatureofinfants’speechperception:categoricalperception.Categoricalperceptionoccurswhenarangeofstimulithatdiffercontinuouslyareperceivedasbelongingtoonlyafewcategorieswithnodegreesofdifferencewithinthosecategories.
Actualstimuli
Perceptionofstimuli
Categoricalperception
Adultcategoricalperception:VoiceOnsetTime(VOT)
60ms
Categoricalperception
Adultcategoricalperception:VoiceOnsetTime(VOT)
[tæ]
[dæ]
Voiceonsettimeinmsec
%ofresponsesaseither[tæ]or[dæ]
Categoricalperception
Adultcategoricalperception:VoiceOnsetTime(VOT)
Decisionbetweendæ/tæ Timetomakedecision
Categoricalperception
Adultcategoricalperception:VoiceOnsetTime(VOT)
Decisionbetweendæ/tæ Timetomakedecision
Uncertaintyatcategoryboundary
Categoricalperception
Adultcategoricalperception:VoiceOnsetTime(VOT)
0ms
20ms
40ms
20ms
40ms
60ms
D T
D
T T
D
Within-categorydiscriminationishard,across-categorydiscriminationiseasy
http://www.thelingspace.com/episode-4https://www.youtube.com/watch?v=dtf8zGQj9GY
5:39-6:59
Categoricalperception
Categoricalperception
Infantcategoricalperception:VoiceOnsetTime(VOT)
Eimasetal.1971:HAStechniqueacrosscategory
withincategory
control(baseline)
Categoricalperception
Infantcategoricalperception:VoiceOnsetTime(VOT)
Eimasetal.1971:HAStechnique
Infantsnotice,comparedtocontrol
acrosscategory
withincategory
control(baseline)
Categoricalperception
Infantcategoricalperception:VoiceOnsetTime(VOT)
Eimasetal.1971:HAStechnique
Infantsdon’tnotice,comparedtocontrol
acrosscategory
withincategory
control(baseline)
Categoricalperception
Infantcategoricalperception:Impactonlaterlanguagedevelopment
FromCurtin&Zamuner2014(Box1):Infantabilitytodiscriminatetwo
acousticallydistinctvowels(/u/and/y/)atsixmonthsiscorrelatedwithlanguageabilitiesat13–24monthsofage(Tsaoetal.2004).
Categoricalperception
Categoricalperception:aspecialhumanability?
Categoricalperceptionisnotspecifictothehumanear,though-it’safeaturesharedwithothermammalslikechinchillas(testedwithanAvoidanceConditioningProcedure)!
Avoidanceconditioningprocedure
■ Speechsoundatoneendofthecontinuumpairedwithshock■ Otherendpairedwithsafety
0 20 40 60 80
VOT
SafetyShock
Avoidanceconditioningprocedure
Animalslearnto“avoid”shock.
Whatwilltheydoforbetweencases?
0 20 40 60 80
VOT
SafetyShock
=FLEE
=STAY? ? ?? ? ?
Kuhl&Miller(1978)
Whycategoricalperceptionissohelpful:Thelackofinvarianceproblem
“…notwounerancesofaparocularphoneme—forexample,the/p/inpick—areidenocal….mightsomeomesproduceher/p/soundwithaVOTof70ms,someomeswithaVOTof90ms….mightproduce/p/withrelaovelyshorterVOTs….[or]pronouncethesoundwithlongerVOTs.Addtothatthefactthatthesoundsabuqngthe/p/willbleedintotheconsonant;the/p/soundinpick,forexample,isacousocallydifferentfromthe/p/soundinpoke.Aninfinitenumberofacous^cpa_ernscanmapintoasinglespeechsound.”
-Myers2017,onthelackofinvarianceproblem
Whycategoricalperceptionissohelpful:Thelackofinvarianceproblem
“…Toconvinceyourselfofhowdifficultitcanbetotranslateacousoccuesintowords,tryanycommerciallyavailablespeech-recogniooninterfacesuchasApple’sSiriorAmazon’sAlexa.Sayasingle,monosyllabicwordsuchaspackclearlyandslowly,andthesystemisreasonablylikelytoidenofyitcorrectly.However,ifyourepeatthewordpackquickly,youmaygetamulotudeofresponses;indifferenttries,SirithoughtIwassayingback,beck,talk,andpart.”
-Myers2017,onthelackofinvarianceproblem
Whycategoricalperceptionissohelpful:Thelackofinvarianceproblem
“….thehumanspeechsystemdoesnotdelivertheenoreauditorycontenttothepointofconsciousawareness.Rather,weusuallycanperceiveonlyacous^cdifferencesthatma_erformeaning…maybeinplacetohelpourbrain’slimitedresourcesfocusononlythemostimportantaspectsofthespeechsignal.”
-Myers2017,ontheuolityofcategoricalpercepoon
Infant-directedspeech
Thenatureofinfant-directedspeech
Motherese/infant-directedspeech/child-directedspeech
Intonationalcontourisgreatlyexaggerated:- higher-pitchedvoice,widerrangeof
pitches,longerpauses,shorterphrases,slowertempo(vowelsareprolonged)
Motheresecouldbehelpfulforlanguagelearning:likelytohighlightimportantfeaturesofspeech,andprovidemoreprototypicalexamplesofalanguage’sspeechsounds
Howmotheresehelps
Greaterdiscriminabilityofphonemes(contrastingsoundsinalanguage)inchild-directedspeechmayhelpchildrenestablishphonemiccategories(thatsignalmeaningcontrasts)
[b]and[p]aredistinctphonemiccategoriesinEnglish. Weknowbecause“big”isadifferentwordfrom“pig”.
Support:Motherswhoproducemorediscriminablevowelsintheirinfant-directedspeechhaveinfantswhodemonstratebetterspeechperceptionskillsinlaboratorytests.
Howmotheresehelps…adults?
Golinkoff&Alioto1995:adultslearnedwordsinaforeignlanguagebetterifthewordswerepresentedininfant-directedratherthanadult-directedspeech
Butnotmothereseforeveryone…
Whilemotheresemaybeveryuseful,itcan’tberequiredforlanguageacquisition(evenifit’sreallyhelpful)sincenotallculturesuseit.Somecultures(ex:Samoans,PapuaNewGuineans,Mayans,USAfricanAmericansintheruralsouth)donotaddressspeechtoprelinguisticchildrenatall-sothosechildrenmustlearnsomeotherway.
Conboy,Brooks,Meltzoff,&Kuhl2015:10-month-oldswhoengagedinmoregazeshifting(whenababymakeseyecontactandthenlooksatthesameobjectthattheotherpersonislookingat)duringsessionswithaforeignlanguagetutorshowedaboostinabrainresponsethatindicateslanguagelearning.
Whatthismeans:Soundlearningmaybegreatlyfacilitatedbythesekindofsocialcuesinacommunicativecontext.
Linksbetweensocialcuesandsoundlearning
https://www.sciencedaily.com/releases/2015/07/150727100024.htm
Recap:Speechsounddevelopment
Thereareseveralexperimentaltechniquesthatcanbeusedtoexamineinfantspeechperception.Oneusefulabilityinfantsseemtohaveiscategoricalperception.Itcanhelpwiththelackofinvarianceproblemforspeechsounds.
Infant-directedspeech(motherese)tendstohaveseveralpropertiesthatmakeithelpfulforlearningthesoundsofthelanguage.
Questions?
Youshouldbeabletodoupthrough9onHW3,andupthrough16onthephonologicaldevelopmentreviewquestions.
